Method and apparatus for corrugating tubes

ABSTRACT

This invention comprises a tube corrugating method and apparatus in which a forming tool is selectively engaged forcefully with and disengaged from the tube while the tube advances axially past the tool. The tube may be pressurized internally with a fluid to improve corrugation shape.

United States Patent Howard F. Matti] Yonkers, N .Y.

Nov. 27, 1968 May 25, 1971 Phelps Dodge Copper Products Corporation New York, N.Y.

lnventor App]. No. Filed Patented Assignee METHOD AND APPARATUS FOR CORRUGATING TUBES 15 Claims, 5 Drawing Figs.

References Cited UNITED STATES PATENTS Park Pogany et a1.

Bruegger Smith et a1... Tobia Stetka Primary Examiner-Richard J. Herbst Attorney-Davis, Hoxie, Faithful] & l-lapgood ABSTRACT: This invention comprises a tube corrugating method and apparatus in which a forming tool is selectively engaged forcefully with and disengaged from the tube while the tube advances axially past the tool. The tube may be pressurized internally with a fluid to improve corrugation shape.

Patented May 25, 1971 3 Sheets-Shut 5 Af/omeys METHOD AND APPARATUS FOR CORRUGATING TUBES BACKGROUND This invention relates to a method and apparatus for corrugating tubes and, more particularly, to a method and apparatus for continuously working tubes to form alternately corrugated and uncorrugated portions.

Corrugated tubing has demonstrated improved efficiencies in heat transfer applications due to a combination of increased fluid turbulence and increased heat exchanger surface area provided by the corrugations. However, it is necessary that the heat exchanger tubes also have uncorrugated or smooth portions at specified locations in order to permit fabrication and assembly of heat exchanger systems. For example, the tubes must be uncorrugated at joint locations where the tube is joined or mated with another tube or fitting in order to assure attainment of a fluidtight seal without the use of intricate sealing means. Prior'art corrugating methods and apparatus automatically continuously corrugate tubing; however, they are incapable of providing uncorrugated portions at predetennined positions along the tubing for predetermined lengths without disrupting the continuity of operation of the apparatus. Furthermore, prior art devices are limited in ability to form deep corrugations of unifonn contour. Where several parallel corrugations are formed, prior art devices often cause collapse of the tube surfaces between indentations resulting in an alternate series of flats and crests rather than the desired continuous series of crests.

Accordingly, it is one object of this invention to provide a method and apparatus for automatically and continuously forming tubing having alternating corrugated and uncorrugated portions of predetermined lengths, whether the tubing is of indeterminate length or of fixed or random lengths.

It is another object of the invention to provide a method and apparatus for continuously forming a plurality of continuous corrugations having substantial depth and improved contour and uniformity.

SUMMARY Briefly stated, this invention, in one form, provides for the continuous, longitudinal, nonrotational movement of a tube past a plurality of forming tools. The fonning tools may rotate about the tube axis and are provided with automatic control means for effecting radial reciprocating movement of the fonning tools relative to the tube. Movement of the forming tools radially inwardly toward the tube axis causes the tools to depress their respective points of contact on the tube an amount equal to the depth of corrugation desired. Combined axial movement of the tube and rotational movement of the tools produce helical corrugations. Upon receipt of a signal, such as from limit switches along the path of movement of the tube, the tools are retracted from the tube or, in other words, moved radially outwardly, while they continue to rotate about the tube axis and while the tube continues to travel longitudinally past the tools. Retraction of the tools and continued travel of the tube results in leaving an uncorrugated tubular portion. After the tube has moved a predetermined distance, the tools are caused to move radially inwardly again to form additional helical corrugations.

In order to improve the formation of properly contoured, uniform, deep corrugations, the tube is pressurized internally. A pressure relief valve is provided to maintain a constant pressure as the internal volume of the tube is reduced by the corrugations being formed.

DESCRIPTION OF THE DRAWINGS The objects and advantages of the present invention will become apparent and better understood from the following description and claims, taken together with the accompanying drawings in which,

FIG. I is a partial sectional, side elevational view of tube corrugating apparatus formed in accordance with this invention,

FIG. 1A is a schematic illustration of the power drive system for the apparatus of FIG. 1,

FIG. 2 is an enlarged end view of the tool holder of the ap- I paratus of FIG. 1 taken along the line 2-2,

FIG. 3 is a sectional view of the tool holder of FIG. 2, taken along the line 3-3, and

FIG. 4 is a schematic representation of a hydraulic system and seal for internally pressurizing the tube being corrugated.

DETAILED DESCRIPTION Tube Support Referring now to the drawings and, more particularly, to FIG. I, there is illustrated a preferred form of the tube corrugating apparatus 8 of this invention. The corrugating apparatus 8 primarily includes a mounting frame, 10 to which is fixedly attached a support housing 12. A hollow sleeve 13 is supported by the housing 12 and is split longitudinally at one end 14 to form a plurality of chuck fingers 15, each being outwardly flared on its outer surface. Adjacent to the other. end 16 of the sleeve 13 is an externally threaded portion 17. Surrounding the sleeve 13 and coacting therewith is a stationary sleeve 18 fixedly mounted within the housing 12. The end of the sleeve 18 adjacent to the fingers 15 has an internal diameter less than the largest outer diameter of the sleeve 13 at its corresponding end 14in order tooperate the chuck fingers 15 in a manner to be described.

A tube 20 to be corrugated is advanced through the sleeve 13 by any conventional means, such as a grip caterpillar 22 having a plurality of spaced tube clamping devices which automatically grip the tube to advance and then release the tube. Caterpillars of this type are well known in the art, one form being described in the US. Pat. No. 3,023,300 dated Feb. 29, 1962. By means of the chuck fingers 15 the sleeve can be adjusted to accept tubes of slightly different diameters. Rotation of a locknut 23, which is mated with the threaded portion 17 of the sleeve 13, in a counterclockwise direction causes the sleeve to advance toward the right in FIG. 1 which free the chuck fingers 15 from the sleeve 18 allowing the fingers to expand and receive the tube 20. After the tube extends slightly past the end 14 of the sleeve 13, the locknut is rotated carefully clockwise causing the sleeve 13 to move toward the left in FIG. 1. Such movement forces the flared end of the fingers 15 to abut against the stationary sleeve 18 resulting in contraction of the fingers against the tube 20 to provide the required tube support without inhibiting axial movement of the tube through the sleeve.

Fonning Tool Support The tube 20 is advanced past a plurality of corrugation forming tools 24 which are supported for radial movement toward and away from the tube axis 26 by tool holders 28. The tool holders 28 are, in turn, fixed to a faceplate 30 which is mounted for rotational movement about the tube axis 26 on the stationary hollow spindle 18. Each forming tool 24 produces a corrugation and the number of tools utilized is determined by the number of corrugations desired within the space limitations of tube diameter.

The faceplate 30 is formed of a circular disc 32 and an annular rim 34 suitably fixed to the disc 32, such as by welds 36. The rim 34 is provided on its periphery with a plurality of cogs 38 to provide a driving interface with a conventional timing belt 40 to rotate the faceplate 30. The radially inner end 42 of the disc 32 is welded to an elongated sleeve 44 which surrounds the stationary hollow sleeve 18. An enlarged portion 46 of the sleeve 44 receives the outer race 48 of a ball bearing 50, the inner race 52 being mounted on the stationary sleeve 18 and held thereon bya locknut 53. The other end of the sleeve 44 is supported for rotary motion about the stationary sleeve 18 by conventional bearing means, such as roller bearings 54 having a grease seal 56 adjacent thereto.

Removably attached to the faceplate 3.0 are a plurality of equally spaced tool holders 28, one of which is illustrated in greater detail in FIGS. 2 and 3. The faceplate for a 1 inch diameter tube is machined to accept two, three, four, five, six, eight, or equally spaced tool holders 28. The apparatus 8 can be set up to produce any of these numbers of corrugations. Each tool holder 28 includes a housing 58 which is attached to the faceplate 30 by conventional bolt means, the housing 58 having a slide passageway 60 partially therethrough. Mounted within the passageway 60 is a slide 62 which is provided with a counterbored cylindrical recess 64 at the lower end 66 thereof. Received within the recess 64 is the shank 68 of a tool support 69 having a yoke-shaped radially inner end 70. The corrugation forming tool 24, such as a forming roll or wheel 72, is rotatably supported on the radially inner end 70 of the tool support 69. The peripheral contour of the wheel 72 has the desired contour of the corrugations to be formed thereby. The shank 68 is formed at its upper end with a tapered portion 74 ending in a shoulder 76. The generally cylindrical form of the shank 68 permits the tool support 69 to rotate about aradialaxis 78 through the tool holder 28, in order to permit adjustment of the alignment of the wheel 72 with respect to the tube axis 26 thereby adjusting the helix angle to suit the pitch of the corrugation being formed. In order to lock the tool support 69 in the proper position for the desired helix angle, a clamp 80, in the form of a bolt, extends transversely through the tool holder housing 58 contiguous to the tapered portion 74 of the tool support shank 68. The bolt bears against the shank to lock it firmly in place.

Forming Tool Actuation Means The radially outer end 82 of the slide 62 is in the form of a yoke (as may be seen in FIG. 2) and supported within the yoke is a roller 84. The roller 84 is supported by a shaft 86 which extends through the slide 62 and through apertures 88, 90 on opposite sides of the housing 58. Each outer end of the shaft 86 is provided with a groove 92 to receive one end of a coil spring 94. The other end of the coil spring 94 is attached to the protruding end of a pin 96 extending outwardly from the radially outer end of the housing 58. Since the slide 62 is free to move within the housing 58 the coil springs bias the slide in a radially outwardly direction away from the tube axis 26. Rotatably mounted within the housing 58 adjacent to and aligned with the roller 84 is a second roller 98. Aligned apertures 100, 102 extend through the faceplate disc 32 and rear wall 103 of the tool holder housing 58 respectively at a position aligned with the rollers 84, 98. Another aperture 104 extends through the front wall 106 of the tool holder housing 58, which aperture also is in alignment with the apertures 100, 102. The purpose of these apertures 100, 102, 104, is to permit passage of a wedge pin 108 through the housing 58 and between the rollers 84 and 98 in the manner and for the purpose described below.

A wedge pin control disc 110 is supported by a cylindrical sleeve 111, which is slideably mounted on the faceplate sleeve 44. A pair of diagonally spaced studs 112, fixed at one end to the disc 32, extend through apertures 113, in the control disc 110 to align the wedge pin 108 with the rollers 84, 98 and to provide joint rotational movement of the faceplate 30 and control disc 110 while permitting relative axial movement of the control disc 110 with respect to the faceplate 30. The I wedge pin 108 is pivotally attached, as at 114, to a retracting lug 116 which, in turn, is supported by the control disc 110. As may be seen in FIG. 3, the wedge pin 108 has parallel walls 120,121 at the front end thereof which then gradually diverge for a short distance until the walls 120, 121 become parallel once again, as is illustrated at 122. The difference between the widths of the parallel portions of the wedge pin 108 represents the travel distance of the slide 62 and wheel 72 since the wedge pin 108 normally resides with the narrower end of the pin between the adjacent rollers 84, 98 as may be seen in FIG. 2. Therefore, the wedge pin 108 determines the depth of corrugation. The corrugation depth can be adjusted also by a depth adjusting screw 123 mounted through the faceplate rim 34 in alignment with an adjustment block 124 forming the top of the tool holder 28. The adjustment block 124 is provided with a threaded recess to receive a clamp screw 125 which extends through an elongated hole 141, through a sidewall of the tool holder. When it is desired to adjust the corrugation depth, the clamp screw 125 is loosened and the adjusting screw 123 is moved in an appropriate direction, positioning the adjustment block. The adjustment block 124, being yoke shaped, supports the upper roller 98.

When it is desired to effect movement of the wheel 72 radially inwardly in order to form corrugations in the tube 20 the wider portion of the wedge pin 108 is inserted between the rollers 84 and 98. Since the outer roller 98 is fixed in position by the clamp screw 125 and adjustment block 124, the force exerted by the wedge pin 108 is transmitted through the inner roller 84 to the slide 62 causing it to move radially inwardly against the biasing force of the coil spring 94. In order to provide the axial movement to the wedge 108 a collar 126 is mounted about the control disc sleeve 112. Supporting the collar 126 are roller thrust bearings 128, 130 which permit the sleeve 111 and control disc 110 to rotate while the collar is stationary. To provide the axial movement to the collar 126 a bellcrank 132, pivotally mounted on two ears 134 extending from the mounting frame 10, is pinned to the collar 126. The other end of the bellcrank 132 is connected to a shaft of a reciprocating motor, for example, a pneumatic motor 136. Actuation of the motor effects pivoting of the bellcrank 132 clockwise in FIG. 1 which forces the collar 126 to slide axially toward the faceplate 30. Such movement forces the wedge pin 108 between the rollers 84, 98 resulting in placement of the wheel 72 in the corrugation forming position. After the tube 20 has traveled a predetermined distance past the wheel 72' and the desired length of tubing has been corrugated, a signal, such as from a limit switch, actuates the motor 136 causing collar 126 to translate away from the faceplate 30 resulting in partial retraction of the wedge pin 108 from between the rollers 84, 98 to the position wherein the narrowest portion of the pin 108 resides between the rollers. It will be appreciated that there is a corresponding wedge pin 108 for each forming tool 24 and insertion and retraction of the wedge pins take place simultaneously with rotation of the faceplate 30 and translation of the tube 20. When the wedge pin 108 is retracted, the combination of the retraction force of the coil springs 94 and centrifugal force immediately drives the slide 62 and the wheel 72 radially outwardly away from the tube 20.

As may be seen by reference to FIG. 1A, the entire tube corrugating apparatus 8 is driven by a variable speed drive motor 138 which, through suitable conventional transmission means, drives the faceplate 30, the motor 136, and the grip caterpillar 22. Suitable clutch means to effect operation of the motor 136 is actuated by signals received from switches or a programmed source. Where tubing of indeterminate length is being corrugated the entire operation may be programmed such that predetermined lengths of tubing will be corrugated and will alternate with predetermined uncorrugated portions. Where fixed length tubing is being corrugated limit switches placed at specific locations along the travel of the tube 20 will provide the signals to the motor clutch.

Tube Pressurizing System With the tube corrugating apparatus 8 described above, there are limitations in the depth to which corrugations can be formed without causing collapse of the tube wall resulting in an alternate series of flats and crests around the periphery of the tube 20 rather than the desired continuous series of crests. The depth to which corrugations can be accurately formed depends upon tube diameter, tube wall thickness, tube material, and corrugation density. In order to increase the depth to which accurate corrugations may be formed and to improve the contour and uniformity of the corrugations the tube 20 may be pressurized inten ally with a fluid. FIG. 4 schematically illustrates a hydraulic system 140 for pressurizing a tube of predetermined length and maintaining the pressure constant as the tube 20 traverses the corrugating apparatus and is corrugated.

To seal one end 141 of the tube 20, a hollow plug 142 (see enlarged section) having a bore 143 axially therethrough is fitted partially within one end of the tube 20. The portion of the plug 142 within the tube has a diameter approximately equal to the inside diameter of the tube. The plug 142 is then reduced providing a tapered reduction shoulder 144. Surrounding the plug is an annular ferrule 146 having a tapered forward end 148. The ferrule 146 is locked onto the plug 142 by a locknut 150 which also urges the ferrule toward the tube 20. As can be seen, when the locknut 150 is tightened against the ferrule 146 forcing the ferrule against the tube 20, the tube is deformed against the plugs shoulder 144 forming a fluid tight seal therewith.

In order to pressurize the tube 20, a conventional hydraulic pump 152 communicates with the tube through the bore 143 in the plug 142. The system 140 also includes a pressure control valve 154, a pressure gauge 156, and a vent reservoir 158.

The opposite end 160 of the tube 20 is closed by a similar sealing means. If a .hollow plug 142 is used, a cap 162 is sealingly mounted on the end of the plug, however, the plug; 162 can be avoided by using a solid plug (not shown) having the same configuration as plug 142.

Before the corrugating process is commenced, the hydraulic pump 152 pressurizes the tube to a desired level. For 1 inch cupro nickel tubing, a pressure of about 1800 p.s.i. has proved successful. As the'tube 20 becomes corrugated, the tubes inte'rnal volume is reduced continually tending to increase the fluid pressure; however the pressure control valve 154 maintains the pressure relatively-constant by bleeding off some fluid into the vent reservoir 158. After the tube has been corrugated the plugs 142 are removed and the deformed tube ends are severed from the tube.

Operation of Corrugation Apparatus The corrugating apparatus described above operates as follows. The drive motor 138 is turned on resulting in rotation of the face plate 30 and forming tools 24 about the tube axis 26 and operation of the grip caterpillar 22. A tube 20 to be corrugated is fed at a desired speed through the sleeve 131 If desired or required due to the depth or shape of the corrugations, the tube 20 can be pressurized. Usually it is preferred to not corrugate the initial portion of the tube since the tube end will probably be joined to a fitting. Therefore, after a predetermined length of tubing is allowed to pass the forming tools 24, the motor 136 is actuated causing the wedge pin 108 to be fully inserted between the rolls 84; 98. Insertion of the wedge pin 108 causes the slide 62 and forming tools 24 to move radially inwardly a distance equal to the desired depth of corrugation. It should be remembered that at this point in time the face plate 30 is rotating about the tube axis 26. The combined axial movement of the tube 20 and rotational movement of the forming tools 24 about the tube axis 26 provides helical corrugations with the helix angle being determined by the orientation of the fonning wheel 72. The pitch of the helix is determined by the rotational speed of the face plate 30 and the translational speed of the tube 20. The corrugating process continues for a predetermined time interval or for apredetermined length of tube, depending upon whether a programmed or switch operated control means is employed. When it is desired to cease corrugating the tube, a signal is transmitted to the motor 136 which effects counterclockwise pivoting of the bell crank 132 and causes the collar 126 to move away from the face plate 30 effecting partial retraction of the wedge pin 108. The combination of the force of the retracting coil springs 94 and the centrifugal force caused by rotation of the face plate causes the slide 62 and forming tools 24 to move radially outwardly immediately while the face plate continues to rotate and the tube 20 continues to travel past the forming tools 24. When it is desired to continue forming corrugations,

the cycle is repeated. lf tubing of indeterminate length is corrugated, the tubing can be cut to proper size at the conclusion of the corrugating process by conventional tube cutting means, such as flying shears (not shown).

The corrugating apparatus described above utilizes a timing belt 40.0r some other motor means to rotate the face plate 30. It has been found, however, that the faceplate can be rotated by the force. of the translating tube 20 against the forming wheel 72 when the drive belt 40 is disconnected. The tube 20, being forcefully moved past the forming wheel 72 exerts a force against the wheel normal to the plane of the wheel. This force is the vector sum of a component parallel to the tube axis 26 and normal to the tube axis, with the normal component effecting rotation of the faceplate 30. The speed of rotation and the pitch of the corrugations is proportional to the angle of the wheel 72 and consequently, may be varied by adjusting the angular position of the forming wheel. If the forming wheel angle is zero or, in other words, if the forming wheel is aligned with the tube axis 26, a plurality of longitudinal, parallel corrugations will be formed.

It can be seen that the apparatus 8 described above provides significant flexibility in the corrugating process. The length of tubing to be corrugated, the locations of the corrugations, and the length of uncorrugated portions can easily be determined and adjusted to fit various applications. Similarly, the helix angle, pitch, and the depths of corrugations can also be adjusted easily. 7

What I claim as new and desire to be secured by letters patent of the United States is:

1. Apparatus for continuously forming a tube with alternating corrugated and uncorrugated portions comprising i a. a head;

b. means for advancing the tube axially relative to the head;

c. a corrugation forming tool mounted on the head and adapted to forcefully engage the periphery of the tube;

d. actuating means for selectively effecting engagement and disengagement of the corrugation forming tool with the tube while the tube advances axially relative to the head; wherein e. the means for mounting the forming tool provides for movement of the tool toward and away from the tube and includes biasing means normally urging the forming tool away from the tube;

f. the means for effecting engagement and disengagement of the forming tool and tube includes forming tool moving means opposing the biasing means effecting movement of the tool toward the tube a predetermined distance and control means for actuating the forming tool moving means in accordance with a predetermined pattern to determine the length of corrugated and uncorrugated tube portion;

g. the forming tool mounting means includes a tool holder mounted on the head and having a radially oriented slideway therein, a tool support slideably mounted within the slideway, the forming tool being mounted on the radially inner end of the tool support and a first bearing member being mounted on the radially outer end thereof, a second bearing member mounted on the tool holder adjacent to the first bearing member, the biasing means normally urging the tool support radially outwardly; and

h. the means for effecting engagement and disengagement of the forming tool and tube comprises a pin mounted for reciprocating movement between the first and second bearing members, whereby insertion of the pin between the bearing members forces the tool support radially inwardly toward the tube and, upon retraction of the pin, the biasing means forces the tool support radially outwardly away from the tube.

2. Apparatus for continuously forming a tube with alternating corrugated and uncorrugated portions comprising a. a head;

b. means for advancing the tube axially relative to the head;

c. a corrugation forming tool mounted on the head and adapted to forcefully engage the periphery of the tube;

d. actuating means for selectively effecting engagement and disengagement of the corrugation forming tool with the tube while the tube advances axially relative to the head;

wherein the means for mounting the forming tool provides for movement of the tool toward and away from the tube and includes biasing means normally urging the forming tool away from the tube; the means for effecting engagement and disengagement of the forming tool and tube includes forming tool moving means opposing the biasing means efi'ecting movement of the tool towardthe tube a predetermined distance and control means for actuating the forming tool moving means in accordance with a predetermined pattern to determine the length of corrugated and uncorrugated tube portion;

g. the forming tool mounting means includes a tool holder mounted on the head, adjusting means for fixing the distance between the tool holder and the tube axis, the tool holder having a radially oriented slideway therein, a slide within the slideway and maintained therein by spring means urgingthe slide radially outwardly from the tube axis, the slide having a recess in the radially inner end thereof, a tool support having a cylindrical shank supported within the recess by adjustable clamping means, the clamping means, when in a first position, allowing rotation of the tool support about an axis transverse to the tube axis and, when in a second position, fixedly holding the tool support within the slide, a first roller rotatably mounted on the radially outer end of the slide and a second roller rotatably mounted on tool holder adjacent to first roller;

h. the forming tool is a wheel rotatably mounted on the radially inner end of the tool support, the peripheral contour of the wheel being the desired contour of the corrugations formed thereby and;

i. the forming tool and tube engaging means comprises a pin mounted for reciprocating movement between the first and second rollers, whereby insertion of the pin between the rollers forces the tool radially inwardly toward the tube and, upon retraction of the pin, the spring means urges the forming tool radially outwardly away from the tube.

3. Apparatus as defined in claim 1 wherein the pin has a first portion of constant width, a second portion of constant width greater than the first portion spaced therefrom, and a tapered intermediate portion and wherein the pin is mounted for movement in a direction parallel to the tube axis from a first position in which the first portion resides between the rollers to a second position in which the second portion resides between the rollers, the difference in width between the first portion and the second portion being equal to the desired depth of corrugation.

4. Apparatus as defined in claim 2 wherein the head is mounted for rotation about the tube axis and the actuating means selectively effects engagement and disengagement of the corrugation forming tool with the tube while the head rotates about the tube axis forming helical corrugations in the tube.

5. Apparatus as defined in claim 3 wherein the head is mounted for rotation about the tube axis and the actuating means selectively effects engagement and disengagement of the corrugation forming tool with the tube while the head rotates about the tube axis forming helical corrugations in the tube.

6. Apparatus for continuously forming alternating corrugated and uncorrugated portions on a tube comprising a. a head mounted for rotation about a first axis;

b. means for rotating the head;

c. means for advancing the tube axially relative to the head,

the tube axis being coaxial with said first axis;

d. a plurality of equally spaced corrugation fonning tools adapted to forcefully engage the periphery of the tube as the head rotates;

e. mounting means for selectively arranging a desired number of the forming tools equally spaced on the head;

f. means for selectively effecting simultaneous engagement and disengagement of the corrugation forming tools with the tube while the tube is advanced axially relative to the head and while the head is rotated about said first axis;

g. each forming tool mounting means includes a tool holder mounted on the head and having a radially oriented slideway therein, a tool support slideably mounted within the slideway, the forming tool being mounted on the radially inner end of the tool support and a first bearing member being mounted on the radially outer end thereof, a second bearing member mounted on the tool holder adjacent to the first bearing member, and biasing means normally urgingthe tool support radially outwardly; and

h. each forming tool and tube engaging and disengaging means comprises a pin mounted for movement between the first and second bearing members, whereby insertion of the pin between the bearing members forces the tool support radially inwardly toward the tube and, upon retraction of the rod, the biasing means forces the tool support radially outwardly away from the tube.

7. Apparatus as defined in claim 6 wherein each pin is connected at one end to an annular control disc, the control disc being coupled to the head for joint rotational movement therewith and for movement relative thereto parallel to the tube axis, and including means for moving the control disc axially toward and away from the head to effect simultaneous movement of the pins between their respective first and second bearing members.

8. Apparatus for continuously forming alternating corrugated and uncorrugated portions on a tube comprising a head disposed radially about periphery tube, a forming tool secured within said head and mounted for radial translations with respect to the tube, means for biasing said forming tool radially outward with respect to said tool, means for advancing tubeaxially relative to said head, means for rotating said head relative to the tube,actuating means for selectively urging said forming tool radially inward against the outer periphery of said tube, said actuating means being secured for rotation with said head, and means mounted about tube axis for selective axial translation therealong for selectively engaging said actuating means for urging said forming tool against the tube periphery.

9. Apparatus as defined in claim 8 including a fluid, tube pressurizing system, the system including means for sealing each end of the tube, means for injecting a fluid under pressure into the tube, and pressure control means for maintaining the fluid pressure within the tube within a predetermined range.

10. Apparatus for continuously forming alternating corrugated and uncorrugated portions on a tube comprising a head having a corrugation fonning tool mounted thereon, means for advancing the tube axially relative to the forming tool, means for providing relative rotational movement between the forming tool and the tube about the tube axis, means for selectively effecting forceful engagement of the forming tool with the tube while the tube advances axially relative to the forming tool, a fluid, tube pressurizing system, the system including means for sealing each end of the tube, means for injecting a fluid under pressure into the tube, pressure control means for maintaining the fluid pressure within the tube within a predetermined range, wherein the means for sealing at least one end of the tube comprises a. a plug having a bore therethrough, one end of the plug having a diameter substantially equal to the inside diameter of the tube and a reduction shoulder adjacent thereto; b. an annular member surrounding the plug adjacent to the shoulder; and c. means for urging the annular member toward said one end of the plug whereby the tube is deformed by the annular member against the shoulder forming a fluidtight seal.

11. Apparatus as defined in claim wherein the fluid injection means is in fluid flow communication with the bore through the plug.

12. Apparatus as defined in claim 10 including means for obturating the plug bore.

13. Apparatus as defined in claim 3 including a fluid, tube pressurizing system, the system including means for sealing each end of the tube, means for injecting a fluid under pressure into the tube, and pressure control means for maintaining the fluid pressure within the tube within a predetermined range.

UNITED STATES PATENT OFFICE 5B9 CERTIFICATE OF CORRECTION Patent No- 3,580,024 Dated May 25, 1971 Inventor) HOWARD F. MATTIL It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

In claim 8, line 6:

"tool" should read --tube-- (SEAL) Attest:

EDWARD M.FLETGHER,JR. Attesting Officer ROBERT GOTTSCHALK Commissioner of Patents 

1. Apparatus for continuously forming a tube with alternating corrugated and uncorrugated portions comprising a. a head; b. means for advancing the tube axially relative to the head; c. a corrugation forming tool mounted on the head and adapted to forcefully engage the periphery of the tube; d. actuating means for selectively effecting engagement and disengagement of the corrugation forming tool with the tube while the tube advances axially relative to the head; wherein e. the means for mounting the forming tool provides for movement of the tool toward and away from the tube and includes biasing means normally urging the forming tool away from the tube; f. the means for effecting engagement and disengagement of the forming tool and tube includes forming tool moving means opposing the biasing means effecting movement of the tool toward the tube a predetermined distance and control means for actuating the forming tool moving means in accordance with a predetermined pattern to determine the length of corrugated and uncorrugated tube portion; g. the forming tool mounting means includes a tool holder mounted on the head and having a radially oriented slideway therein, a tool support slideably mounted within the slideway, the forming tool being mounted on the radially inner end of the tool support and a first bearing member being mounted on the radially outer end thereof, a second bearing member mounted on the tool holder adjacent to the first bearing member, the biasing means normally urging the tool support radially outwardly; and h. the means for effecting engagement and disengagement of the forming tool and tube comprises a pin mounted for reciprocating movement between the first and second bearing members, whereby insertion of the pin between the bearing members forces the tool support radially inwardly toward the tube and, upon retraction of the pin, the biasing means forces the tool support radially outwardly away from the tube.
 2. Apparatus for continuously forming a tube with alternating corrugated and uncorrugated portions comprising a. a head; b. means for advancing the tube axially relative to the head; c. a corrugation forming tool mounted on the head and adapted to forcefully engage the periphery of the tube; d. actuating means for selectively effecting engagement and disengagement of the corrugation forming tool with the tube while the tube advances axially relative to the head; wherein e. the means for mounting the forming tool provides for movement of the tool toward and away from the tube and includes biasing means normally urging the forming tool away from the tube; f. the means for effecting engagement and disengagement of the forming tool and tube includes forming tool moving means opposing the biasing means effecting movement of the tool toward the tube a predetermined distance and control means for actuating the forming tool moving means in accordance with a predetermined pattern to determine the length of corrugated and uncorrugated tube portion; g. the forming tool mounting means includes a tool holder mounted on the head, adjusting means for fixing the distance between the tool holder and the tube axis, the tool holder having a radially oriented slideway therein, a slide within the slideway and maintained therein by spring means urging the slide radially outwardly from the tube axis, the slide having a recess in the radially inner end thereof, a tool support having a cylindrical shank supported within the recess by adjustable clamping means, the clamping means, when in a first position, allowing rotation of the tool support about an axis transverse to the tube axis and, when in a second position, fixedly holding the tool support within the slide, a first roller rotatably mounted on the radially outer end of the slide and a second roller rotatably mounted on tool holder adjacent to first roller; h. the forming tool is a wheel rotatably mounted on the radially inner end of the tool support, the peripheral contour of the wheel being the desired contour of the corrugations formed thereby and; i. the forming tool and tube engaging means comprises a pin mounted for reciprocating movement between the first and second rollers, whereby insertion of the pin between the rollers forces the tool radially inwardly toward the tube and, upon retraction of the pin, the spring means urges the forming tool radially outwardly away from the tube.
 3. Apparatus as defined in claim 1 wherein the pin has a first portion of constant width, a second portion of constant width greater than the first portion spaced therefrom, and a tapered intermediate portion and wherein the pin is mounted for movement in a direction parallel to the tube axis from a first position in which the first portion resides between the rollers to a second position in which the second portion resides between the rollers, the difference in width between the first portion and the second portion being equal to the desired depth of corrugation.
 4. Apparatus as defined in claim 2 wherein the head is mounted for rotation about the tube axis and the actuating means selectively effects engagement and disengagement of the corrugation forming tool with the tube while the head rotates about the tube axis forming helical corrugations in the tube.
 5. Apparatus as defined in claim 3 wherein the head is mounted for rotation about the tube axis and the actuating means selectively effects engagement and disengagement of the corrugation forming tool with the tube while the head rotates about the tube axis forming helical corrugations in the tube.
 6. Apparatus for continuously forming alternating corrugated and uncorrugated portions on a tube comprising a. a head mounted for rotation about a first axis; b. means for rotating the head; c. means for advancing the tube axially relative to the head, the tube axis being coaxial with said first axis; d. a plurality of equally spaced corrugation forming tools adapted to forcefully engage the periphery of the tube as the head rotates; e. mounting means for selectively arranging a desired number of the forming tools equally spaced on the head; f. means for selectively effecting simultaneous engagement and disengagement of the corrugation forming tools with the tube while the tube is advanced axially relative to the head and while the head is rotated about said first axis; g. each forming tool mounting means includes a tool holder mounted on the head and having a radially oriented slideway therein, a tool support slideably mounted within the slideway, the forming tool being mounted on the radially inner end of the tool support and a first bearing member being mounted on the radially outer end thereof, a second bearing member mounted on the tool holder adjacent to the first bearing member, and biasing means normally urging the tool support radially outwardly; and h. each forming tool and tube engaging and disengaging means comprises a pin mounted for movement between the first and second bearing members, whereby insertion of the pin between the bearing members forces the tool support radially inwardly toward the tube and, upon retraction of the rod, the biasing means forces the tool support radially outwardly away from the tube.
 7. Apparatus as defined in claim 6 wherein each pin is connected at one end to an annular control disc, the control disc being coupled to the head for joint rotational movement therewith and for movement relative thereto parallel to the tube axis, and including means for moving the control disc axially toward and away from the head to effect simultaneous movement of the pins between their respective first and second bearing members.
 8. Apparatus for continuously forming alternating corrugated and uncorrugated portions on a tube comprising a head disposed radially about periphery tube, a forming tool secured within said head and mounted for radial translations with respect to the tube, means for biasing said forming tool radially outward with respect to said tool, means for advancing tube axially relative to said head, means for rotating said head relative to the tube, actuating means for selectively urging said forming tool radially inward against the outer periphery of said tube, said actuating means being secured for rotation with said head, and means mounted about tube axis for selective axial translation therealong for selectively engaging said actuating means for urging said forming tool against the tube periphery.
 9. Apparatus as defined in claim 8 including a fluid, tube pressurizing system, the system including means for sealing each end of the tube, means for injecting a fluid under pressure into the tube, and pressure control means for maintAining the fluid pressure within the tube within a predetermined range.
 10. Apparatus for continuously forming alternating corrugated and uncorrugated portions on a tube comprising a head having a corrugation forming tool mounted thereon, means for advancing the tube axially relative to the forming tool, means for providing relative rotational movement between the forming tool and the tube about the tube axis, means for selectively effecting forceful engagement of the forming tool with the tube while the tube advances axially relative to the forming tool, a fluid, tube pressurizing system, the system including means for sealing each end of the tube, means for injecting a fluid under pressure into the tube, pressure control means for maintaining the fluid pressure within the tube within a predetermined range, wherein the means for sealing at least one end of the tube comprises a. a plug having a bore therethrough, one end of the plug having a diameter substantially equal to the inside diameter of the tube and a reduction shoulder adjacent thereto; b. an annular member surrounding the plug adjacent to the shoulder; and c. means for urging the annular member toward said one end of the plug whereby the tube is deformed by the annular member against the shoulder forming a fluidtight seal.
 11. Apparatus as defined in claim 10 wherein the fluid injection means is in fluid flow communication with the bore through the plug.
 12. Apparatus as defined in claim 10 including means for obturating the plug bore.
 13. Apparatus as defined in claim 3 including a fluid, tube pressurizing system, the system including means for sealing each end of the tube, means for injecting a fluid under pressure into the tube, and pressure control means for maintaining the fluid pressure within the tube within a predetermined range.
 14. Apparatus as defined in claim 7 including a fluid, tube pressurizing system, the system including means for sealing each end of the tube, means for injecting a fluid under pressure into the tube, and pressure control means for maintaining the fluid pressure within the tube within a predetermined range.
 15. A combination as in claim 8 further comprising at least one additional forming tool mounted for selective radial translation within said head. 